British Airways said it has frozen tens of thousands of frequent flyer accounts after the company suffered a cyber attack, and the airline apologised to customers for the inconvenience.

The airline owned by International Airlines Group (IAG) confirmed that customers' personal information such as names, addresses and bank details was not stolen in the attack, however they would not be able to use their accumulated air miles for the time being.

The company, which has millions of customers, expects to resolve the problem in a few days.

"British Airways has become aware of some unauthorised activity in relation to a small number of frequent flyer Executive Club accounts," a company spokesman said in a statement sent to IB Times UK.

"We would like to reassure customers that, at this stage we are not aware of any access to any subsequent information pages within accounts, including travel histories or payment card details."

"We are sorry for the concern and inconvenience this matter has caused, and would like to reassure customers that we are taking this incident seriously and have taken a number of steps to lock down accounts so they can no longer be accessed," the spokesman added.

The hacker/hackers behind the attack are yet to be identified. It is believed that the hackers accessed the company's computers with the help of an automated computer programme that looks for vulnerabilities in online security systems.